| Abstract
| - We study the impact of surface chemistry on the photoluminescence (PL) quantum yield of CdSe core, CdSe/CdS core/shell, and CdSe/CdZnS/ZnS core/shell/shell nanocrystals prepared by multiple synthetic routes.We expose as-synthesized particles to varying concentrations of n-alkylamine and n-alkanethiol ligands andverify that the addition of n-alkanethiols to CdSe and CdSe/CdS nanocrystal solutions quenches their PL. Wealso show that the addition of n-alkylamines to nanocrystal solutions can increase or decrease nanocrystalPL, an effect that depends on the concentration of both nanocrystals and ligands. We demonstrate the importanceof considering the nanocrystal concentration when fitting ligand binding curves, and show that common solventimpurities can affect the PL and ligand binding data. While alkanethiols quench CdSe nanocrystals preparedusing multiple synthetic procedures, we find the exact shape of the quenching curve depends on the syntheticroute chosen. We emphasize that the ligand binding data extracted from PL quenching curves are contingenton the assumptions made during fitting. By fitting our PL quenching curves to a Langmuir isotherm andaccounting for the particle surface sites, we estimate a lower limit for the equilibrium CdSe−alkanethiolbinding constant on the order of 109 M-1 with different numbers of thiol binding sites depending on themethod of nanocrystal synthesis.
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